def test_max_depth_1(self):
     tree = Node.Node(5, None, None)
     self.assertEqual(1, TreeOperations.maximum_depth(tree))
 def test_max_depth_2_right(self):
     tree = Node.Node(5, None, Node.Node(3, None, None))
     self.assertEqual(2, TreeOperations.maximum_depth(tree))
 def test_max_depth_empty(self):
     self.assertEqual(0, TreeOperations.maximum_depth(None))